Authors of electronic documents often create lists and other sequential or grouped content structures (e.g., numbered chapters, sections, footnotes, bibliographic entries, etc.) without using a list-editing tool or otherwise specifying the list as a semantic structure in the document. In addition, even if the author encodes this structure in the document, the structure may be lost when printing to a PDF through a virtual printer driver.
When the list information is not explicit in the structure of the document, this prevents various applications from using features that take advantage of such lists. Applications are unable to suggest additional list entries for a user, cannot navigate a document as easily, or copy portions of a list as accurately.